graph/example/filtered_graph.cpp

//=======================================================================
// Copyright 2001 University of Notre Dame.
// Author: Jeremy G. Siek
//
// Distributed under the Boost Software License, Version 1.0. (See
// accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//=======================================================================

/*
   Sample output:

   filtered edge set: (A,B) (C,D) (D,B)
   filtered out-edges:
   A --> B
   B -->
   C --> D
   D --> B
   E -->
 */

#include <boost/config.hpp>
#include <iostream>
#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/filtered_graph.hpp>
#include <boost/graph/graph_utility.hpp>

template < typename EdgeWeightMap > struct positive_edge_weight
{
    positive_edge_weight() {}
    positive_edge_weight(EdgeWeightMap weight) : m_weight(weight) {}
    template < typename Edge > bool operator()(const Edge& e) const
    {
        return 0 < boost::get(m_weight, e);
    }
    EdgeWeightMap m_weight;
};

int main()
{
    using namespace boost;

    using Graph = adjacency_list< vecS, vecS, directedS, no_property,
        property< edge_weight_t, int > >;
    using EdgeWeightMap = property_map< Graph, edge_weight_t >::type;

    enum
    {
        A,
        B,
        C,
        D,
        E,
        N
    };
    const char* name = "ABCDE";
    Graph g(N);
    add_edge(A, B, 2, g);
    add_edge(A, C, 0, g);
    add_edge(C, D, 1, g);
    add_edge(C, E, 0, g);
    add_edge(D, B, 3, g);
    add_edge(E, C, 0, g);

    positive_edge_weight< EdgeWeightMap > filter(get(edge_weight, g));
    filtered_graph< Graph, positive_edge_weight< EdgeWeightMap > > fg(
        g, filter);

    std::cout << "filtered edge set: ";
    print_edges(fg, name);

    std::cout << "filtered out-edges:" << std::endl;
    print_graph(fg, name);

    return 0;
}